3 School of Pathology, University of the
Witwatersrand, Johannesburg, South Africa

4Amayeza
Drug Information Centre, Johannesburg, South Africa

5Department
of Family Medicine, University of Pretoria, South Africa

6Division
of Clinical Pharmacology, Department of Medicine, University
of Cape Town, South Africa

7Department
of Health, Polokwane, Limpopo, South Africa

8Department
of Health, Nelspruit, Mpumalanga, South Africa

9Department
of Health, Jozini, KwaZulu-Natal, South Africa

10National
Department of Health, Pretoria, South Africa

Corresponding
author: N Morris
(nmorrism@gmail.com)

Background. Malaria case numbers reported in
South Africa have reduced considerably over the last decade,
necessitating a revision of the national risk map to guide
malaria prevention, including the use of chemoprophylaxis.

Objectives. To update the national malaria
risk map based on recent case data and to consider the
implications of the new transmission profile for guiding
prophylaxis.

Methods. The geographical distribution of
confirmed malaria cases detected both passively and actively
over the last six malaria seasons was used to redefine the
geographical distribution and intensity of malaria
transmission in the country.

Results. The national risk map was
revised to reflect zones of transmission reduced both in their
extent and their intensity.Most notably, the area of risk
has been reduced in the north-western parts of Limpopo
Province and is limited to the extreme northern reaches of
KwaZulu-Natal Province. Areas previously considered to be of
high risk are now regarded to be of moderate risk.

Conclusion. Chemoprophylaxis is now only
recommended from September to May in the north-eastern areas
of Limpopo and Mpumalanga Provinces. The recommended options
for chemoprophylaxis have not changed from mefloquine,
doxycycline or atovaquone-proguanil.

S Afr Med J 2013;103(11):861-864.
DOI:10.7196/SAMJ.7533

Malaria in South Africa
(SA) is endemic in the north-eastern reaches of the three
provinces of KwaZulu-Natal (KZN), Limpopo and Mpumalanga. The
risk of infection peaks during the summer rainfall season,
typically between September and May. The predominant malaria
species is Plasmodium falciparum, transmitted by two main vector
species, namely Anopheles
arabiensis and Anopheles gambiae.

Malaria case notifications
of <10000 annually between 1950 and
1990 escalated sharply during the epidemic of the 1999/2000
season, reaching over 60000 cases nationally with some
41400 of these reported in KZN.
Strengthened and sustained vector control and case-management
strategies using artemisinin-based combination therapy (ACT)
were coupled with the implementation of a regional
cross-border collaborative programme between SA, Swaziland and
Mozambique aimed at extending effective vector control and
malaria diagnosis
and treatment into border areas of neighbouring countries.1 Massive reductions were
realised in all sectors, most notably by some 90% in northern
KZN between 1999 and 2004.2,3

SA has actively controlled
malaria since the 1940s using the World Health Organization
(WHO) recommended strategies of: vector control; case
management; surveillance; and information, education and
communication (IEC).4 Through these interventions, SA
has succeeded in reducing the burden of the disease and is now
targeting malaria elimination (zero local malaria cases) by
the year 2018.5

It is imperative that healthcare
workers are adequately informed of appropriate drug and
non-drug measures for the prevention of malaria. In keeping
with the National Guidelines for Malaria Prevention,
healthcare workers need to know where travellers intend to
visit, before recommending appropriate preventive strategies
and prescribing chemoprophylaxis, if indicated.6 An up-to-date malaria risk map
is therefore required to guide chemoprophylactic and non-drug
protective measures.

The national malaria risk map,
last updated in 2007, has been revised based on recent data and
reflects risk zones that are reduced both in geographical extent
and malaria transmision intensity. Redefining the malaria risk
profile in SA provides an opportunity to revisit national
recommendations for precaution and prevention.

Objective

We define the criteria used to review the malaria risk map for
SA and provide advice on chemoprophylactic and non-drug measures
for the prevention of the disease.

Methods

Malaria risk in SA was depicted in 1938 as affecting much
of (then) Natal and the northern and eastern lowveld,
extending as far as Port St Johns in the south and Pretoria
and the Orange River in the north-west (Fig. 1).7 The
official map depicting malaria risk in the country was next
revised in 2000, informed by case notifications and evidence
of the presence of suitable vectors, and depicted malaria
confined largely to the north-east of the country, bound in
the south by Richards Bay and in the north-east by Louis
Trichardt and Swartwater.

Fig. 1. Malaria risk in 1938 prior to
the implementation of control measures (left) and malaria
risk in 2007 following the implementation of regional
cross-border control (right).

Minor adjustment to the
malaria risk map was made in 2007. This involved drawing the
risk profile as starting further north in KZN where it was
limited to the three northern districts, namely uMkhanyakude,
Uthungulu and Zululand. Areas as far north as Lake St Lucia
were declared malaria-free (Fig. 1).8 At this stage, notified malaria
case aggregates at sub-district level provided the primary
indicator of the geographical extent of reported local
infections.

The national malaria case
burden has continued to see sustained reductions to around 10000 annually for the last five
years following a systematic programme of strengthening vector
control coupled with case management using ACT, and a
reduction of both the parasite and vector reservoirs in
neighbouring Swaziland and Mozambique. All nine malarious
districts of SA met elimination criteria in 2013, reporting
<1 case per 1 000 population at risk.

Critical to the success of
the control programme, and indeed the elimination agenda going
forward, has been the implementation of a spatially-enabled
malaria information system (MIS). Individual patient case data
passively notified via health facilities and infections
actively detected by surveillance agents in communities are
recorded within the MIS.9 Malaria cases reported in the
MIS have historically been mapped at district level, with the
exception of KZN where small-scale malaria planning area
boundaries were developed in 1999 using a combination of
global positioning system (GPS) coordinate data and
topographical reference mapping.

A large-scale initiative to map
malaria case data reported through the provincial MISs at the
level of residential locality of all cases notified since 1996,
was embarked upon in 2004 and completed in 2011. This enabled
high-resolution mapping of malaria nationally for the first time
in 2012. This initiative provided a unique opportunity to update
the national malaria risk map, consulting notified case data at
high spatial resolution. Cases were mapped at the locality level
for the last thirteen malaria seasons and stratified by their
probable source of infection. Predominant clusters of
locally-acquired infections over the last five seasons were used
to determine zones of malaria risk in the country. Two broad
categories of low- and moderate-risk areas were defined in
keeping with the dramatically reduced case burden in the country
since the drawing of the 2007 version of the risk map.

The revised malaria risk profile
boundary was developed, based on malaria incidence rates over
the past five years at municipality level, and then adjusted
intra-municipally, taking cognisance of known malaria incidence
at locality level.

Results

In June 2013, the South African Malaria Elimination Committee
(SAMEC) reached agreement over the geographical distribution and
intensity of malaria risk captured in the updated malaria risk
map (Fig. 2).

Fig. 2. Official malaria risk map for
South Africa, 2013.

The key changes from the 2007
version of the risk map include the following:

1. The northern-most area of KZN
previously denoted as a ‘risk area’ is now classified as a ‘low
risk area’. The low risk area previously extending as far south
as Richards Bay has now been scaled back to end further north
around the Mtubatuba and Mfolozi areas.

2. The low risk profile in the
northern provinces of Limpopo and Mpumalanga has been scaled
back in line with a reduced incidence of local malaria case
notifications observed in the western parts of these provinces.
Most notably, the low risk area in Limpopo, previously extending
as far west as Swartwater, now ends east of Alldays, with the
moderate risk area ending east of Musina. Although a fair number
of cases are reported at Musina, they are typically imported
infections associated with border crossings in the proximity of
the town.

3. Previous guidance appearing on
the risk map referring visitors to country-specific maps for
further risk profile information for neighbouring countries has
been amended to refer instead to the WHO international travel
health guidelines.

4. The colour scheme and
terminology of the risk classes have been adjusted in line with
the substantial reductions in malaria risk observed nationally.
The high risk area previously in red has been scaled back as
noted in (1) and (2) above, and is now referred to as a
‘moderate risk’ area depicted in a lighter shade.

5. An inset map of SA has been
added on the right indicating the malarious provinces and risk
areas within national bounds.

The official risk map, now
endorsed by the National Department of Health, has been updated
with due consideration given to actual notified case data in the
malarious provinces, and takes into account the intended
audience, namely those providing travel advice.

Discussion

Implications
for prevention

The decision of whether to recommend malaria chemoprophylaxis
to a traveller requires consideration of the risk of contracting
malaria in the specific area at the specific time, as well as
the risk of adverse effects of any chemoprophylaxis prescribed.
The revised malaria risk map, based on actual notified case
data, enables the health professional to assess more accurately
the risk to the traveller of contracting malaria. Previously,
chemoprophylaxis was recommended during the warm wet season in
the northern parts of KZN and in the north-eastern areas of
Limpopo and Mpumalanga. Based on the new data, chemoprophylaxis
is now only recommended from September to May in the
north-eastern areas of Limpopo and Mpumalanga.

The recommended options for
chemoprophylaxis have not changed and remain the following:6

• Mefloquine – from
5 kg
(or 3 months of age), a weekly dose started at least 1 week
prior to entering the malaria area, once weekly while there and
once weekly for 4 weeks after leaving the area.

• Doxycycline –
from 8 years of age, a daily dose started at least 1 day before
entering the area, once daily while in the area and once daily
for 4 weeks after leaving the area.

• Atovaquone-proguanil
– from 11 kg,
a daily dose started at least 1 day before entering the area,
once daily while in the area and once daily for 7 days after
leaving the area.

Stringent non-drug measures
should be taken to avoid mosquito bites throughout the year, in
areas of both low and moderate malaria-transmission intensity.
Measures that reduce contact with mosquitoes have the advantage
that they are less toxic than chemoprophylactic drugs and that
their effectiveness does not depend on the drug sensitivity of
the parasite. These measures include:6

• Remaining indoors
between dusk and dawn.

• Wearing
long-sleeved clothing, long trousers and socks when going out at
night.

• Covering doorways
and windows with screens but, if not available, windows and
doors should be closed at night.

• Applying an
N,N-diethyl-meta-toluamide (DEET)-containing insect repellent to
exposed skin; repeat as recommended on the container label.
Avoid eyelids, lips, sunburnt or damaged skin, do not spray on
the face and do not overdose young children.

• Using mosquito
mats impregnated with an insecticide (heated electrically or by
a non-electric lamp), or burning mosquito coils in living and
sleeping areas during the night.

• Using a
mosquito-proof bed net over the bed, with edges tucked in,
ensuring that the net is not torn and that there are no
mosquitoes inside. Protection will be increased by treating the
net periodically with an insecticide registered for this
purpose; e.g. a pyrethroid.

• Spraying inside
the house with an aerosol insecticide (for flying insects) at
dusk, especially the bedrooms, after closing the windows.

• Using ceiling
fans and air conditioners.

• Treating clothes
with an insecticide registered for this purpose; e.g. a
pyrethroid.

Conclusion

An accurate national
malaria risk profile is necessary to inform prophylaxis
guidelines. High-resolution mapping of individual case
notification data at the locality level has enabled an
accurate assessment of the geographical extent of the
occurrence of local infections. Substantial gains in reducing
the extent and intensity of malaria transmission in SA over
the last decade are now reflected in the revised national risk
map. This data-driven mapping of the malaria risk profile
enables rational recommendations regarding the use of non-drug
and chemoprophylactic measures, thereby supporting the
national malaria prevention guidelines. As
malaria control interventions continue to be strengthened, and
malaria elimination strategies start to be implemented, it is
essential that the risk map is regularly updated. This depends
on all malaria cases being notified promptly.

Acknowledgements. The authors are
grateful to the provincial information officers and GIS
technicians involved in producing the quality data that informed
the update of the national risk map. We record our appreciation
to Mr Ishen Seocharan for maintenance, management and
integration of the MISs at the national level, without which
this exercise would not have been possible. Credit is also due
to the wider membership of the SAMEC, whose expert opinion has
provided the backdrop to the exercise. The authors wish to
acknowledge the important role of healthcare personnel and
surveillance agents in case detection and data collection.

Author contributions. NM, DM, LBK,
ISU, KB, RM and JF drafted the manuscript. LBL and JF reviewed
and edited the manuscript. NM developed the risk map. PK, AM and
ER guided fine-scale adjustments to the risk map. All authors
read, contributed to, and approved the final versions of both
the map and the manuscript.